Multiple-antenna space multiplexing system using enhancement signal detection

ABSTRACT

The multiple-antenna space multiplexing system using enhancement signal detection comprising: a code modulation module for coding and modulating bit information; a signal transmission module for transmitting the modulated signals; a signal reception module for receiving the signals; a signal form transform module for transforming form of a channel matrix H and the received signal vector r; a signal detection module for detecting the received signals; a signal reconstruction module for reconstructing the detection results of in the signal detection module, and obtaining a detected signal; a demodulation decoding module for demodulating and decoding the output of the signal reconstruction module, and outputting bit information. Compared with the conventional detection methods, the system performance is improved in considering the realization complexity.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to transmission of information in amultiple-antenna communication system, especially relates to atechnology of transmission and detection for a multiple-antenna signal.

2. Description of the Related Art

With limited spectrum resources, data transmission rate can be improvedeffectively by using the multiple-antenna space multiplexing BLASTtechnology.

The existing BLAST detection algorithm may be divided to lineardetection (including Zero-Forcing detection (ZF), Minimum Mean SquareError Detection (MMSE) . . . ) and nonlinear detection (includingZero-Forcing and signal Interference Cancellation detection (ZF-SIC),Minimum mean Square Error and signal Interference Cancellation detection(MMSE-SIC) . . . ).

The linear detection method is easy to be realized relatively, whilewith poor performance. Compared with the linear detection method, thenonlinear detection method may improve the performance of the system.However the significantly increased complexity caused by iterativeinterference cancellation is the main difficulty for the nonlineardetection to be put into practice.

The following is a simple outline of linear and nonlinear BLASTdetection algorithm.

Linear Detection Algorithm

Assuming the received signal is

r=Hs+n,

where, H is a N×M Channel Matrix, s is an M-dimensional transmissionsignal vector, r is a N-dimensional receipt signal vector, n is aN-dimensional independent white Gaussian noise, M and N are the numbersof system transmitting and receiving antennas.

For Zero-Forcing detection algorithm,

ŝ _(ZF)=(H ^(H) H)⁻¹ H ^(H) r=s+(H ^(H) H)⁻¹ H ^(H) n.

For MMSE (Minimum mean square error detection) algorithm,

ŝ _(MMSE)=(H ^(H) H+σ ² I)⁻¹ H ^(H) r=s+(H ^(H) H+σ ² I)⁻¹ H ^(H) n.

where, ŝ_(ZF) and ŝ_(MMSE) are M-dimensional vectors of detected signalsunder different algorithms respectively.

Nonlinear Detection Algorithm

Compared with the linear detection, the nonlinear detection technologymay improve the system performance effectively at the price of increaseof operation complexity.

The following gives an outline of sequential interference cancellationalgorithm in the BLAST nonlinear detection algorithm. The basicprinciple of this algorithm is to remove the interference coming fromthe detected parts in the process of detecting the current signals, soas to reduce the impact that interference has on data with smallersignal-to-noise ratio. This principle is similar to the decisionfeedback equalization.

The following describes the detection process:

For ZF-SIC detector, it will defines that

G _(i) =H ^(†)=(H ^(H) H)⁻¹ H ^(H),

For MMSE-SIC detector, it will defines that

G _(i) =H ^(†)=(H ^(H) H+σI)⁻¹ H ^(H).

After Process 1, a decision signal may be obtained:

k _(i) =arg min∥(G _(i))_(j)∥²

w _(k) _(i) =(G _(i))_(k) _(i)

y _(k) _(i) =w _(k) _(i) ^(T) r _(i)

â _(k) _(i) =Q(y _(k) _(i) )  Process 1

In the above process, k₁, k₂, . . . , k_(M) form a sequence oftransmitting antennas in the detection process.

Then, Process 2 is performed and the impact of the detected signals hasbeen removed from the received signals. The new pseudo inverse matrix isdetermined and the new decision sequence is also determined.

$\begin{matrix}\begin{matrix}{r_{i + 1} = \left. {r_{i} - {{\hat{a}}_{k_{i}}(H)}_{k_{i}}}\Rightarrow G_{i + 1} \right.} \\{= \left. H_{i + 1}^{\dagger}\Rightarrow k_{i + 1} \right.} \\{= \left. {\underset{j \notin {\{{k_{1}\mspace{14mu} \ldots \mspace{14mu} k_{i}}\}}}{argmin}{\left( G_{i + 1} \right)_{j}}^{2}}\Rightarrow i\leftarrow{i + 1} \right.}\end{matrix} & {{Process}\mspace{14mu} 2}\end{matrix}$

Then a cyclical process is formed, and the cyclical process includesProcess 1 and Process 2, the cyclical process is carrying out on thesignals until i=M. Now, all signals have been determined, and thecyclical process is completed.

The BLAST linear detection method is easy to be realized relatively,while with poor performance. Compared with the linear detection method,the nonlinear detection method can improve the performance of thesystem. However the significantly increased complexity caused by theiterative interference cancellation is the main difficulty for thenonlinear detection to be put into practice.

SUMMARY OF THE INVENTION

This invention provides a BLAST system using enhancement signaldetection. Complexity of this system is close to a BLAST system using atraditional linear detector and the performance of system according topresent invention is better than the BLAST system using sequentialinterference cancellation nonlinear detector.

In order to realize the above object, a multiple-antenna spacemultiplexing system using enhancement signal detection comprising:

a code modulation module for coding and modulating bit information;

a signal transmission module for transmitting the modulated signals;

a signal reception module for receiving the signals;

a signal form transform module for transforming form of channel matrix Hand the received signal vector r;

a signal detection module for detecting the received signals;

a signal reconstruction module for reconstructing the detection resultsof in the signal detection module, and obtaining a detected signal{tilde over (s)};

a demodulation decoding module for demodulating and decoding the outputof the signal reconstruction module, and outputting bit information.

Compared with the ZF and the ZF SIC detection method, the BERperformance of this system in this invention are improved significantly.Compared with the above detection methods, in this invention, thisinvention has more advantages in considering the system performance,improvement and realization complexity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows system architecture of transmitting end according to thisinvention;

FIG. 2 shows system architecture of receiving end and the signaling flowend according to this invention;

FIG. 3 shows bit error rate (BER) performance.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The system architecture and signaling flow according to this inventionare shown in FIG. 1 and FIG. 2.

An outline of this system architecture is described in the followings:

Code modulation module for coding and modulating the bit information.

Signal transmission module for transmitting the modulated signals. Theprinciples of this module consist in that: the signal waiting to betransmitted is s, assuming that quasi-static fading channel H remainsthe same between adjacent time block T₁ and T₂. In time block T₁, thetransmission signal is s_(T) ₁ =Re(s)+jIm(s), in time block T₂, thetransmission signal is s_(T) ₂ =Im(s)+jRe(s). Re(s) indicates a realpart of the complex signal, Im(s) indicates an imaginary part of thecomplex signal.

Signal reception module for receiving the signals, r_(T) ₁ =Hs_(T) ₁+n_(T) ₁ , r_(T) ₂ =Hs_(T) ₂ +n_(T) ₂ .

Signal form transform module for transforming the form of channel matrixH and the received signal vector r:

${H_{1} = \begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}},{H_{2} = \begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}},{r_{T_{1}}^{\prime} = \begin{bmatrix}{{Re}\left( r_{T_{1}} \right)} \\{{Im}\left( r_{T_{1}} \right)}\end{bmatrix}},{r_{T_{2}}^{\prime} = {\begin{bmatrix}{{Re}\left( r_{T_{2}} \right)} \\{{Im}\left( r_{T_{2}} \right)}\end{bmatrix}.}}$

Signal detection module for detecting the received signals:

${{{Re}\left( \overset{\sim}{s} \right)} = {0.5 \times {\begin{bmatrix}H_{1}^{+} & H_{2}^{+}\end{bmatrix}\begin{bmatrix}r_{T_{1}}^{\prime} \\r_{T_{2}}^{\prime}\end{bmatrix}}}},{{{Im}\left( \overset{\sim}{s} \right)} = {0.5 \times {{\begin{bmatrix}H_{1}^{+} & H_{2}^{+}\end{bmatrix}\begin{bmatrix}r_{T_{1}}^{\prime} \\r_{T_{1}}^{\prime}\end{bmatrix}}.{{Re}\left( \overset{\sim}{s} \right)}}}}$

is a real part of the detected signal, Im(s) is an imaginary part of thedetected signal.

Signal reconstruction module for reconstructing the signal detectionresults, then obtaining the detected signal {tilde over (s)}. Thereconstruction principle: {tilde over (s)}=Re({tilde over(s)})+jIm({tilde over (s)}).

Demodulation and decoding module for demodulating and decoding thedetected signal, then outputting bit information.

According to the above process, in the process of signal detection ofthis system, a pseudo inverse detection matrix

$\begin{bmatrix}{{Re}(H)} & {- {{Im}(H)}} \\{{Im}(H)} & {{Re}(H)}\end{bmatrix}^{+}$

in conventional detection algorithms is degenerated to

${\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}^{+}\mspace{14mu} {{and}\mspace{14mu}\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}}^{+}},$

which will reduce noise raise in the process of detection obviously. Atthe same time, compared with the conventional linear detectionalgorithm, the complexity of this system has not been raised obviously.The complexity is far lower than the sequential interferencecancellation nonlinear detection algorithm

The following is to prove the rationality of the signaling process inthe system according to this invention:

In the following proving process, [ ]⁺ means matrix pseudo inverse, []^(H) means matrix transpose conjugate.

At the receiving end, assuming r _(T) ₁ =Hs _(T) ₁ +n _(T) ₁ , r _(T) ₂=Hs _(T) ₂ +n _(T) ₂   (1)

Performing equivalent transformation on expression (1)

$\begin{matrix}\begin{matrix}{r_{T_{1}}^{\prime} = {\begin{bmatrix}{{Re}\left( r_{T_{1}} \right)} \\{{Im}\left( r_{T_{1}} \right)}\end{bmatrix} = {{\begin{bmatrix}{{Re}(H)} & {- {{Im}(H)}} \\{{Im}(H)} & {{Re}(H)}\end{bmatrix}\begin{bmatrix}{{Re}\left( s_{T_{1}} \right)} \\{{Im}\left( s_{T_{1}} \right)}\end{bmatrix}} + \begin{bmatrix}{{Re}\left( n_{T_{1}} \right)} \\{{Im}\left( n_{T_{1}} \right)}\end{bmatrix}}}} \\{= {{\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}{{Re}(s)}} + {\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}{{Im}(s)}} + \begin{bmatrix}{{Re}\left( n_{T_{1}} \right)} \\{{Im}\left( n_{T_{1}} \right)}\end{bmatrix}}}\end{matrix} & (2) \\\begin{matrix}{r_{T_{2}}^{\prime} = {\begin{bmatrix}{{Re}\left( r_{T_{2}} \right)} \\{{Im}\left( r_{T_{2}} \right)}\end{bmatrix} = {{\begin{bmatrix}{{Re}(H)} & {- {{Im}(H)}} \\{{Im}(H)} & {{Re}(H)}\end{bmatrix}\begin{bmatrix}{{Re}\left( s_{T_{2}} \right)} \\{{Im}\left( s_{T_{2}} \right)}\end{bmatrix}} + \begin{bmatrix}{{Re}\left( n_{T_{2}} \right)} \\{{Im}\left( n_{T_{2}} \right)}\end{bmatrix}}}} \\{= {{\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}{{Im}(s)}} + {\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}{{Re}(s)}} + \begin{bmatrix}{{Re}\left( n_{T_{2}} \right)} \\{{Im}\left( n_{T_{2}} \right)}\end{bmatrix}}}\end{matrix} & (3) \\{Then} & \; \\\begin{matrix}{{H_{1}^{+}r_{T_{1}}^{\prime}} = {\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}^{+}\begin{bmatrix}{{Re}\left( r_{T_{1}} \right)} \\{{Im}\left( r_{T_{1}} \right)}\end{bmatrix}}} \\{= {\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}^{+}\begin{pmatrix}{{\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}{{Re}(s)}} +} \\{{\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}{{Im}(s)}} + \begin{bmatrix}{{Re}\left( n_{T_{1}} \right)} \\{{Im}\left( n_{T_{1}} \right)}\end{bmatrix}}\end{pmatrix}}} \\{= {{{Re}(s)} + {{\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}^{+}\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}}{{Im}(s)}} +}} \\{{\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}^{+}\begin{bmatrix}{{Re}\left( n_{T_{1}} \right)} \\{{Im}\left( n_{T_{1}} \right)}\end{bmatrix}}}\end{matrix} & (4) \\\begin{matrix}{{H_{2}^{+}r_{T_{1}}^{\prime}} = {\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}^{+}\begin{bmatrix}{{Re}\left( r_{T_{1}} \right)} \\{{Im}\left( r_{T_{1}} \right)}\end{bmatrix}}} \\{= {\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}^{+}\begin{pmatrix}{{\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}{{Re}(s)}} +} \\{{\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}{{Im}(s)}} + \begin{bmatrix}{{Re}\left( n_{T_{1}} \right)} \\{{Im}\left( n_{T_{1}} \right)}\end{bmatrix}}\end{pmatrix}}} \\{= {{{\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}^{+}\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}}{{Re}(s)}} + {{Im}(s)} +}} \\{{\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}^{+}\begin{bmatrix}{{Re}\left( n_{T_{1}} \right)} \\{{Im}\left( n_{T_{1}} \right)}\end{bmatrix}}}\end{matrix} & (5) \\\begin{matrix}{{H_{1}^{+}r_{T_{2}}^{\prime}} = {\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}^{+}\begin{bmatrix}{{Re}\left( r_{T_{2}} \right)} \\{{Im}\left( r_{T_{2}} \right)}\end{bmatrix}}} \\{= {\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}^{+}\begin{pmatrix}{{\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}{{Im}(s)}} +} \\{{\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}{{Re}(s)}} + \begin{bmatrix}{{Re}\left( n_{T_{1}} \right)} \\{{Im}\left( n_{T_{1}} \right)}\end{bmatrix}}\end{pmatrix}}} \\{= {{{Im}(s)} + {{\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}^{+}\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}}{{Re}(s)}} +}} \\{{\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}^{+}\begin{bmatrix}{{Re}\left( n_{T_{1}} \right)} \\{{Im}\left( n_{T_{1}} \right)}\end{bmatrix}}}\end{matrix} & (6) \\\begin{matrix}{{H_{2}^{+}r_{T_{2}}^{\prime}} = {\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}^{+}\begin{bmatrix}{{Re}\left( r_{T_{1}} \right)} \\{{Im}\left( r_{T_{1}} \right)}\end{bmatrix}}} \\{= {\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}^{+}\begin{pmatrix}{{\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}{{Im}(s)}} +} \\{{\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}{{Re}(s)}} + \begin{bmatrix}{{Re}\left( n_{T_{1}} \right)} \\{{Im}\left( n_{T_{1}} \right)}\end{bmatrix}}\end{pmatrix}}} \\{= {{{\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}^{+}\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}}{{Im}(s)}} + {{Re}(s)} +}} \\{{\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}^{+}\begin{bmatrix}{{Re}\left( n_{T_{1}} \right)} \\{{Im}\left( n_{T_{1}} \right)}\end{bmatrix}}}\end{matrix} & (7) \\{{the}\mspace{14mu} {following}\mspace{14mu} {is}\mspace{14mu} {to}\mspace{14mu} {prove}\mspace{14mu} {that}} & \; \\{{\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}^{+}\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}} = {- {\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}^{+}\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}}}} & (8) \\\begin{matrix}{{\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}^{+}\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}} = \left( {\begin{bmatrix}{{Re}^{H}(H)} & {{Im}^{H}(H)}\end{bmatrix}\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}} \right)^{- 1}} \\{{\begin{bmatrix}{{Re}^{H}(H)} & {{Im}^{H}(H)}\end{bmatrix}\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}}} \\{= \left\lbrack {{{{Re}^{H}(H)}{{Re}(H)}} + {{{Im}^{H}(H)}{{Im}(H)}}} \right\rbrack^{- 1}} \\{\left\lbrack {{{- {{Re}^{H}(H)}}{{Im}(H)}} + {{{Im}^{H}(H)}{{Re}(H)}}} \right\rbrack}\end{matrix} & (9) \\\begin{matrix}{{\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}^{+}\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}} = \left( {\begin{bmatrix}{- {{Im}^{H}(H)}} & {{Re}^{H}(H)}\end{bmatrix}\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}} \right)^{- 1}} \\{{\begin{bmatrix}{- {{Im}^{H}(H)}} & {{Re}^{H}(H)}\end{bmatrix}\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}}} \\{= \left\lbrack {{{{Im}^{H}(H)}{{Im}(H)}} + {{{Re}^{H}(H)}{{Re}(H)}}} \right\rbrack^{- 1}} \\{\left\lbrack {{{- {{Im}^{H}(H)}}{{Re}(H)}} + {{{Re}^{H}(H)}{{Im}(H)}}} \right\rbrack}\end{matrix} & (10)\end{matrix}$

Expression (8) may be proved from expression (9) and (10).

Then

$\begin{matrix}\begin{matrix}{{0.5 \times {\begin{bmatrix}H_{1}^{+} & H_{2}^{+}\end{bmatrix}\begin{bmatrix}r_{T_{1}}^{\prime} \\r_{T_{2}}^{\prime}\end{bmatrix}}} = {0.5 \times \left\lbrack {{H_{1}^{+}r_{T_{1}}^{\prime}} + {H_{2}^{+}r_{T_{2}}^{\prime}}} \right\rbrack}} \\{= {0.5 \times}} \\{\begin{pmatrix}{{{Re}(s)} + {{\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}^{+}\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}}{{Im}(s)}} +} \\{{\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}^{+}\begin{bmatrix}{{Re}\left( n_{T_{1}} \right)} \\{{Im}\left( n_{T_{1}} \right)}\end{bmatrix}} + \begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}^{+}} \\{{\begin{bmatrix}{{Re}(H)} \\{{Im}(H)}\end{bmatrix}{{Im}(s)}} + {{Re}(s)} +} \\{\begin{bmatrix}{- {{Im}(H)}} \\{{Re}(H)}\end{bmatrix}^{+}\begin{bmatrix}{{Re}\left( n_{T_{1}} \right)} \\{{Im}\left( n_{T_{1}} \right)}\end{bmatrix}}\end{pmatrix}}\end{matrix} & (11)\end{matrix}$

From expression (8) and (11), we may get:

$\begin{matrix}{{{Re}\left( \overset{\sim}{s} \right)} = {0.5 \times {\begin{bmatrix}H_{1}^{+} & H_{2}^{+}\end{bmatrix}\begin{bmatrix}r_{T_{1}}^{\prime} \\r_{T_{2}}^{\prime}\end{bmatrix}}}} & (12)\end{matrix}$

Similarly,

$\begin{matrix}{{{Im}\left( \overset{\sim}{s} \right)} = {0.5 \times {\begin{bmatrix}H_{1}^{+} & H_{2}^{+}\end{bmatrix}\begin{bmatrix}r_{T_{2}}^{\prime} \\r_{T_{1}^{\prime}}\end{bmatrix}}}} & (13)\end{matrix}$

The detected signal is

{tilde over (s)}=Re({tilde over (s)})+jIm({tilde over (s)})  (14)

This embodiment uses a multiple antenna BLAST communication systemconsisting of four transmit four receive antennas. The channel is aquasi-static flat Rayleigh fading channel. Assuming channel remains thesame between the continuous time block T₁ and T₂. In the embodiment, thesystem according to this invention and the BLAST system using ZFdetection and ZF SIC detector are all carried out for performancesimulation. To ensure a fair performance comparison, on the transmittingend, the system according to this invention uses 16QAM modulation, whileZF and ZF SIC algorithm transmitting end use QPSK modulation.

In the simulation, 1/3 Turbo code is used for coding and decoding in allalgorithms.

1. A multiple-antenna space multiplexing system using enhancement signal detection comprising: a code modulation module (101) for coding and modulating bit information; a signal transmission module (102) for transmitting the modulated signals; a signal reception module (201) for receiving the signals; a signal form transform module (202) for transforming form of a channel matrix H and the received signal vector r; a signal detection module (203) for detecting the received signals; a signal reconstruction module (204) for reconstructing the detection results of in the signal detection module, and obtaining a detected signal {tilde over (s)}; a demodulation decoding module (205) for demodulating and decoding the output of the signal reconstruction module, and outputting bit information.
 2. The system according to claim 1, wherein the signal transmission module transmits signals as following principles: a signal waiting to be transmitted is s, assuming that quasi-static fading channel H remains the same between adjacent time block T₁ and T₂; in time block T₁, the transmission signal is s_(T) ₁ =Re(s)+jIm(s); in time block T₂, the transmission signal is s_(T) ₂ =Im(s)+jRe(s), where Re(s) indicates a real part of complex signal, Im(s) indicates an imaginary part of complex signal.
 3. The system according to claim 1, wherein a principle of form transforming of the channel matrix H and the received signal vector r is: ${H_{1} = \begin{bmatrix} {{Re}(H)} \\ {{Im}(H)} \end{bmatrix}},{H_{2} = \begin{bmatrix} {- {{Im}(H)}} \\ {{Re}(H)} \end{bmatrix}},{r_{T_{1}}^{\prime} = \begin{bmatrix} {{Re}\left( r_{T_{1}} \right)} \\ {{Im}\left( r_{T_{1}} \right)} \end{bmatrix}},{r_{T_{2}^{\prime}} = {\begin{bmatrix} {{Re}\left( r_{T_{2}} \right)} \\ {{Im}\left( r_{T_{2}} \right)} \end{bmatrix}.}}$
 4. The system according to claim 1, wherein a principle for the signal detection module detecting the received signals is: ${{{Re}\left( \overset{\sim}{s} \right)} = {0.5 \times {\begin{bmatrix} H_{1}^{+} & H_{2}^{+} \end{bmatrix}\begin{bmatrix} r_{T_{1}}^{\prime} \\ r_{T_{2}}^{\prime} \end{bmatrix}}}},{{{Im}\left( \overset{\sim}{s} \right)} = {0.5 \times {\begin{bmatrix} H_{1}^{+} & H_{2}^{+} \end{bmatrix}\begin{bmatrix} r_{T_{2}}^{\prime} \\ r_{T_{1}}^{\prime} \end{bmatrix}}}}$ ${Re}\left( \overset{\sim}{s} \right)$ is a real part of the detected signal, Im({tilde over (s)}) is an imaginary part of the detected signal.
 5. The system according to claim 1, wherein a principle for the signal reconstruction module reconstructing the signal detection results is: ${{Im}\left( \overset{\sim}{s} \right)} = {0.5 \times {{\begin{bmatrix} H_{1}^{+} & H_{2}^{+} \end{bmatrix}\begin{bmatrix} r_{T_{2}}^{\prime} \\ r_{T_{1}}^{\prime} \end{bmatrix}}.}}$
 6. The system according to claim 1, wherein the antenna is an MIMO antenna. 